Method of producing mat surfaces



Patented Mar. ,31, 1953 METHOD OF-PROD'UCING SURFACES BEING POOR IN ADHESIONON THERMO- PLASTICS Karl Tanner, Rusc'lilikon, Switzerland, assignor to 'Fiirberei Schlieren A. G.,, Schlieren, Switzerland No Drawing. ApplicationJuly15, 1950, SleriaLNo. 114,118. In Switzerland September .2, 1949 '5 Glaims. .1

Fabrics, vfiber. fleece, paper, .etc. being covered v with polyvinyl chloride or other thermoplastics,

or .any products being manufactured from such materials, if they are plasticized .or have a Y certain elasticity .of themselves whichis necessary f. e. for artificial leather like goods, show a great luster and often besides a glutinous surface that presents a moist and disagreeable feel. This disadvantage .is mostly due to the fact that the used thermoplastics .have themselves to be very elastic and soft .or that they must .contain .a largev quantity of plasticizers so asto get the suppleness neededfor these articles. The luster is often undesired and the moist and glutinous feel or the great surface adhesion is in general not appreciated.

.Said disadvantages particularly appearif polyvinyl chloride, copolymerizates or other thermoplastics are spread ,on any vehicle under form of pastes, suspenses .or solutionsor when they.

are worked upotherwiseand dried or gelatinized afterwards.

The reasons for the stickiness of the surface and the high luster are amongst others the following ones:

'On account of the evaporation of the solvent the plasticizers enrich on the surface or the solvents are obstinately .held fast on the surface by the thermoplastics and thus have an additional plasticizing effect.

Pastes being free from vsolvents or suspensions of resins in nonsolvents often. also form those undesirable lustrous .or sticky or moist feeling surfaces.

In thermoplastics to which no plasticizer is added or those which contain plasticizers which do not migrate, such as synthetic rubber.- types, soft resins etc. the uppermost layer, due to the drying or gelatin-izing process melts to an undesired glossy surface. If temperatures below the softening point of the applied thermoplastics are employed, it willsurely be possible to obtain a mat, inadhesive surface but in this case the article will not present the required.

high .gelatinizlngtemperaturegor during the sub-'1 sequent aging process. Thus the luster cannot be reduced.

Moreover it has beentrled to get a mat sur-.

face and .a dry and adhesive-free feel by adding fillers whichdry the-surface up, .or by chemicals being known so far as matting agents. The adendered the particles of these matting agents. are pressed fiat to the surface by the calender.

. Ifthe matting substances .are added to the top coat in such a quantity that the particles do no more melt with the coating, the mechanical resisting power as well as the rubbing strength will diminish, i. e. after a short time of use the surface matted in this manner will become again fat and lustrous.

Another possibilityof matting the surface, e. g. of ,polyvinyl resin coats consists in adding polyvinyl resin of larger particle size to the top coat-paste; thus a mat and relatively dry surface is also obtained. This method, however, is. very :delicate as it will be indispensable to maintain the accurately determined gelatinizing temperatures and as there will arise again irregularities a-nd scrapers in the surface owing to the coarse material applied in the coating process. A compromise is made in the choice of the gelatinizing temperature by choosing just that temperature at which the mass will barely gelatinize.

Thus a great uncertainty arises in production,

because .once the article will become mat but unsufliciently gelatinized, while another time the article will be well gelatinized but no more so mat as required. Besides it will be quite impossible to obtain a throughout uniform matting effect for all goods.

A good matting effect can also be obtained by this that thermoplastics are suspended in organic solvents in which they .are not soluble and that the surface to be matted is coated therewith (the so-calledOrganosol method). This process however shows the great disadvantage that firstly very expensive solvents are to be used and that secondly at a high gelatinizing temperature the thermoplastic particles being caused to swell by the softeners will nevertheless become blent and thus :a good matting effect as well as an absolute ina-dhesiveness cannot be obtained.

A further method consists in matting the nearly ready gelatinized foils or breadths afterwards by treatment with a roughened hot roller or to emboss same directly in the hot state after the gelatinizing process by such a roller. Said rollers can be roughened in several manners, f. e. by sand blast, engraving or cauterizing. Matting then corresponds to a real embossing process as the pores and irregularities of the roller surfaceare impressed into the thermoplastic surface. So as to make this embossed work durable either the article to be embossed or the roller must be heated beyond the softening point of the thermoplastics. tage that it is very expensive because an additional working process is to be put in and that in general irregularly matted surfaces will be the result since the artificial leather or the article to be embossed shows no equal thickness. Furthermore the matting effect will turn out relatively weak and the disagreeable surface adhesiveness will be unsignificantly reduced.

Another possibility of matting the surface consists in roughening same by sand blast. This method shows the great disadvantage that a uniform mat surface can hardly be got, that the process is very expensive and that some colors will alter their shades, as by the sand blast an unhomogeneous surface will be the result.

The present invention relates to a process that eliminates all these disadvantages and thatallows to mat the surfaces of all products made under use of any plastified or unplastified thermoplastics and to give these products a dry, inadhesive, not sticky and agreeable feel.

According to the invention the new method for producing mat surfaces and being poor in ad-- hesion on thermoplastics by treatment with a matting material, comprises the steps that the surface to be treated is covered with a watery suspension of at least one thermoplastic and '4' that the coat will then be fixed by heating.

This method allows to provide materials such as textiles, paper, fiber fleece, f. e. being covered with plasticized or unplasticized thermoplastics,

as for instance polyvinyl resins, but also thermo plastic films without any vehicles, with an absolutely mat, dry, inadhesive and agreeable feel which thus is no more sticky.

As a matting material the same thermoplastic may be used of which the surface to be matted consists, but any other thermoplastics or a thermoplastic mixture may also be used, provided that the matting material adheres well to the ground material or melts together with the latter.

No plasticizer is normally added to the matting material suspended in a more or less fine particle size. In certain cases however a plasticizer may be added but in small quantities only.

The watery matting suspension may be applied by coating, immerging or spraying or by any other method.

The temperature at which the matting suspension will be dried and fixed, f. e. in a furnace, is determined according to the softening point of the ground material. At that temperature the grains of the matting agent swell or melt only there where they get in touch with the surface of this ground material. Thus they will adhere fast and form a microscopically finely roughened surface. The feel is absolutely dry and inadhesive. The binding of the thermoplastic grains with the surface to be matted is highly stronger than in any other matting agent used Said method shows the disadvanso far which will be melted into the surface afterwards because of its compatibility with the ground material and thus being intimately bound with thelatter. The'surface matted in this manner will get no lustereven after a subsequent heating beyond the softening point, as this was the case in all products matted according to the forementioned hitherto known methods.

. Example 1.-The matting paste is produced as follows:

100 parts of a pure polyvinyl chloride are finely ground and mixed with 10 parts of a wetting agent, e. g. of a fatty alcohol sulfonate, 200 parts of water are added and thoroughly stirred. To obtain the necessary coating consistency it is preferable to add a thickening agent, e. g. 35 parts of a four per cent high-grade viscous watersoluble methyl cellulose. The quantity of the thickener will be determined in general according to the coating method, while thequantity of the wetting agent is chosen according tothe degree of fineness of the polyvinyl chloride.

This matting paste is now coated on an arti-j ficial leather-like product built up on the basis of polyvinyl chloride or of a vinyl chloride copolymerisate and plasticizers, and dried and fixed a spreading machine or dried only and subsequently fixed in the gelatinizing furnace. Drying may be efiectuated at temperatures below (3., While fixing is to be made at a temperature at which the vinyl resin-plasticizer mixture" forming the basis for the artificial leather-like product begins softening.

., Example 2.A waterproof cloak fabric coated with plasticized polyvinyl chloride is covered with the following paste:

hydroxymethyl cellulose.

The mackintosh fabric is coated with this mixture, whereafter it is dried and fixed according to the method mentioned by Example 1.

Example 3.A paper coated with a solution of I a copolymer of vinylchloride and vinylacetate in a suitable organic solvent mixture is covered with a paste of the following composition:

100 parts of a copolymer of vinylchloride and' vinylidene chloride are stirred to a paste with 3 parts of a wetting agent, e. g. olein-cetylalcohot sulfonate and parts of water and 50 parts of A a 3 per cent high-grade viscous sodium carboxymethylcellulose added as a thickener. The coated paper will be dried and fixed as mentioned by Example 1.

What I claim and wish to secure by Letters Patent is:

' 1. The method of producing a matt surface on:

a supple lustrous-surfaced plasticized polyvinyl resin base, comprising the steps of: coating said lustrous-surface with a paste containing an aque ous suspension of a finely divided polymer selected from the group consisting of polyvinyl chloride and a copolymer of vinyl chloride with vinylidene chloride, and a wetting agent, said paste being thickened to desired consistency with sodium carbohydroxymethyl cellulose; and heating said coated base to which said paste has been applied to the softening temperature of said finely divided polymer; whereby a microscopically finely roughened surface is produced on said surface of said supple base.

6 REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 1,967,863 Collins et al July 24, 1934 2,311,489 Toland et a1 Feb. 16, 1943 2,385,320 Greene et a1 Sept. 18, 1945 10 2,428,716 McGiel et al Oct. 7, 1947 2,431,745 Flanagan Dec. 2, 1947 

1. THE METHOD OF PRODUCING A MATT SURFACE ON A SUPPLE LUSTROUS-SURFACED PLASTICIZED POLYVINYL RESIN BASE, COMPRISING THE STEPS OF: COATING SAID LUSTROUS-SURFACE WITH A PASTE CONTAINING AN AQUEOUS SUSPENSION OF A FINELY DIVIDED POLYMER SELECTED FROM THE GROUP CONSISTING OF POLYVINYL CHLORIDE AND A COPOLYMER OF VINYL CHLORIDE WITH CINYLIDENE CHLORIDE, AND A WETTING AGENT, SAID PASTE BEING THICKENED TO DESIRED CONSISTENCY WITH SODIUM CARBOHYDROXYMETHYL CELLULOSE; AND HEATING SAID COATED BASE TO WHICH SAID PASTE HAS BEEN APPLIED TO THE SOFTENING TEMPERATURE OF SAID FINELY DIVIDED POLYMER, WHEREBY A MICROSCOPICALLY FINELY ROUGHENED SURFACE IS PRODUCED ON SAID SURFACE OF SAID SUPPLE BASE. 